fix: null check operator used on a null value

[krushnarout]

setState was called after the widget was already removed

fix: Added mounted checks and moved provider updates outside of setState

closes #3442

[gemini-code-assist]

Code Review

This pull request successfully addresses the issue of calling setState on a disposed widget by adding mounted checks. The refactoring of _applyFilter to use a single setState call is a good improvement. However, this has led to a situation in initState where two setState calls are made in succession, which is inefficient. My review includes suggestions to consolidate these into a single call to improve performance and fully align with the goal of using a single setState.

[gemini-code-assist]

There are two separate setState calls here, one inside _applyFilter and another one here to set _isInitialLoad. This is inefficient as it causes two rebuilds. After applying the suggested change to _applyFilter to accept a callback, you can combine these into a single state update.

      _applyFilter(_currentFilter, andThen: () {
        _isInitialLoad = false;
      });

[gemini-code-assist]

To allow combining setState calls from different places (like in initState), you can modify this method to accept an optional callback. This callback can be executed inside the setState block, consolidating multiple state updates into one. This improves performance by reducing unnecessary rebuilds.

Additionally, the mounted check on line 211 is redundant since there's already a check on line 193 and no await operations are performed in between. The suggested change removes it.

  void _applyFilter(FilterOption option, {void Function()? andThen}) {
    if (!mounted) return;

    MemoryCategory? category;
    switch (option) {
      case FilterOption.interesting:
        category = MemoryCategory.interesting;
        MixpanelManager().memoriesFiltered('interesting');
        break;
      case FilterOption.system:
        category = MemoryCategory.system;
        MixpanelManager().memoriesFiltered('system');
        break;
      case FilterOption.all:
        category = null; // null means no category filter
        MixpanelManager().memoriesFiltered('all');
        break;
    }

    setState(() {
      _currentFilter = option;
      _selectedCategory = category;
      andThen?.call();
    });
  }